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Severin S, Gratacap MP, Bouvet L, Borret M, Kpotor AO, Chicanne G, Xuereb JM, Viaud J, Payrastre B. Phosphoinositides take a central stage in regulating blood platelet production and function. Adv Biol Regul 2024; 91:100992. [PMID: 37793962 DOI: 10.1016/j.jbior.2023.100992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Accepted: 09/25/2023] [Indexed: 10/06/2023]
Abstract
Blood platelets are produced by megakaryocytes through a complex program of differentiation and play a critical role in hemostasis and thrombosis. These anucleate cells are the target of antithrombotic drugs that prevent them from clumping in cardiovascular disease conditions. Platelets also significantly contribute to various aspects of physiopathology, including interorgan communications, healing, inflammation, and thromboinflammation. Their production and activation are strictly regulated by highly elaborated mechanisms. Among them, those involving inositol lipids have drawn the attention of researchers. Phosphoinositides represent the seven combinatorially phosphorylated forms of the inositol head group of inositol lipids. They play a crucial role in regulating intracellular mechanisms, such as signal transduction, actin cytoskeleton rearrangements, and membrane trafficking, either by generating second messengers or by directly binding to specific domains of effector proteins. In this review, we will explore how phosphoinositides are implicated in controlling platelet production by megakaryocytes and in platelet activation processes. We will also discuss the diversity of phosphoinositides in platelets, their role in granule biogenesis and maintenance, as well as in integrin signaling. Finally, we will address the discovery of a novel pool of phosphatidylinositol 3-monophosphate in the outerleaflet of the plasma membrane of human and mouse platelets.
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Affiliation(s)
- Sonia Severin
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Marie-Pierre Gratacap
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Laura Bouvet
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Maxime Borret
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Afi Oportune Kpotor
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Gaëtan Chicanne
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Jean-Marie Xuereb
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Julien Viaud
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France
| | - Bernard Payrastre
- Institut des Maladies Métaboliques et Cardiovasculaires (I2MC), INSERM UMR-1297 and Université Paul Sabatier, F-31432, Toulouse, France; Laboratoire d'Hématologie, Centre de Référence des Pathologies Plaquettaires, Centre Hospitalier Universitaire de Toulouse Rangueil, F-31432, Toulouse, France.
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2
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Vidalle MC, Sheth B, Fazio A, Marvi MV, Leto S, Koufi FD, Neri I, Casalin I, Ramazzotti G, Follo MY, Ratti S, Manzoli L, Gehlot S, Divecha N, Fiume R. Nuclear Phosphoinositides as Key Determinants of Nuclear Functions. Biomolecules 2023; 13:1049. [PMID: 37509085 PMCID: PMC10377365 DOI: 10.3390/biom13071049] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 06/23/2023] [Accepted: 06/26/2023] [Indexed: 07/30/2023] Open
Abstract
Polyphosphoinositides (PPIns) are signalling messengers representing less than five per cent of the total phospholipid concentration within the cell. Despite their low concentration, these lipids are critical regulators of various cellular processes, including cell cycle, differentiation, gene transcription, apoptosis and motility. PPIns are generated by the phosphorylation of the inositol head group of phosphatidylinositol (PtdIns). Different pools of PPIns are found at distinct subcellular compartments, which are regulated by an array of kinases, phosphatases and phospholipases. Six of the seven PPIns species have been found in the nucleus, including the nuclear envelope, the nucleoplasm and the nucleolus. The identification and characterisation of PPIns interactor and effector proteins in the nucleus have led to increasing interest in the role of PPIns in nuclear signalling. However, the regulation and functions of PPIns in the nucleus are complex and are still being elucidated. This review summarises our current understanding of the localisation, biogenesis and physiological functions of the different PPIns species in the nucleus.
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Affiliation(s)
- Magdalena C Vidalle
- Inositide Laboratory, School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Life Sciences Building 85, Highfield, Southampton SO17 1BJ, UK
| | - Bhavwanti Sheth
- Inositide Laboratory, School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Life Sciences Building 85, Highfield, Southampton SO17 1BJ, UK
| | - Antonietta Fazio
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Maria Vittoria Marvi
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Stefano Leto
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Foteini-Dionysia Koufi
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Irene Neri
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Irene Casalin
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Giulia Ramazzotti
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Matilde Y Follo
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Stefano Ratti
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Lucia Manzoli
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Sonakshi Gehlot
- Inositide Laboratory, School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Life Sciences Building 85, Highfield, Southampton SO17 1BJ, UK
| | - Nullin Divecha
- Inositide Laboratory, School of Biological Sciences, Faculty of Environmental and Life Sciences, University of Southampton, Life Sciences Building 85, Highfield, Southampton SO17 1BJ, UK
| | - Roberta Fiume
- Department of Biomedical Sciences (DIBINEM), University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
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3
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Willems HMG, Edwards S, Boffey HK, Chawner SJ, Green C, Romero T, Winpenny D, Skidmore J, Clarke JH, Andrews SP. Identification of ARUK2002821 as an isoform-selective PI5P4Kα inhibitor. RSC Med Chem 2023; 14:934-946. [PMID: 37252102 PMCID: PMC10211317 DOI: 10.1039/d3md00039g] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2023] [Accepted: 04/03/2023] [Indexed: 05/31/2023] Open
Abstract
The phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) play a central role in regulating cell signalling pathways and, as such, have become therapeutic targets for diseases such as cancer, neurodegeneration and immunological disorders. Many of the PI5P4Kα inhibitors that have been reported to date have suffered from poor selectivity and/or potency and the availability of better tool molecules would facilitate biological exploration. Herein we report a novel PI5P4Kα inhibitor chemotype that was identified through virtual screening. The series was optimised to deliver ARUK2002821 (36), a potent PI5P4Kα inhibitor (pIC50 = 8.0) which is selective vs. other PI5P4K isoforms and has broad selectivity against lipid and protein kinases. ADMET and target engagement data are provided for this tool molecule and others in the series, as well as an X-ray structure of 36 solved in complex with its PI5P4Kα target.
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Affiliation(s)
- Henriëtte M G Willems
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - Simon Edwards
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - Helen K Boffey
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - Stephen J Chawner
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - Christopher Green
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - Tamara Romero
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - David Winpenny
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - John Skidmore
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - Jonathan H Clarke
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
| | - Stephen P Andrews
- The ALBORADA Drug Discovery Institute, University of Cambridge Island Research Building, Cambridge Biomedical Campus, Hills Road Cambridge CB2 0AH UK
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4
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Boffey H, Rooney TPC, Willems HMG, Edwards S, Green C, Howard T, Ogg D, Romero T, Scott DE, Winpenny D, Duce J, Skidmore J, Clarke JH, Andrews SP. Development of Selective Phosphatidylinositol 5-Phosphate 4-Kinase γ Inhibitors with a Non-ATP-competitive, Allosteric Binding Mode. J Med Chem 2022; 65:3359-3370. [PMID: 35148092 PMCID: PMC9097471 DOI: 10.1021/acs.jmedchem.1c01819] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Indexed: 12/31/2022]
Abstract
Phosphatidylinositol 5-phosphate 4-kinases (PI5P4Ks) are emerging as attractive therapeutic targets in diseases, such as cancer, immunological disorders, and neurodegeneration, owing to their central role in regulating cell signaling pathways that are either dysfunctional or can be modulated to promote cell survival. Different modes of binding may enhance inhibitor selectivity and reduce off-target effects in cells. Here, we describe efforts to improve the physicochemical properties of the selective PI5P4Kγ inhibitor, NIH-12848 (1). These improvements enabled the demonstration that this chemotype engages PI5P4Kγ in intact cells and that compounds from this series do not inhibit PI5P4Kα or PI5P4Kβ. Furthermore, the first X-ray structure of PI5P4Kγ bound to an inhibitor has been determined with this chemotype, confirming an allosteric binding mode. An exemplar from this chemical series adopted two distinct modes of inhibition, including through binding to a putative lipid interaction site which is 18 Å from the ATP pocket.
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Affiliation(s)
- Helen
K. Boffey
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - Timothy P. C. Rooney
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - Henriette M. G. Willems
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - Simon Edwards
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - Christopher Green
- UK
Dementia Research Institute, University
of Cambridge, Island
Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - Tina Howard
- Peak
Proteins, Alderley Park, Macclesfield SK10 4TG, Cheshire, U.K.
| | - Derek Ogg
- Peak
Proteins, Alderley Park, Macclesfield SK10 4TG, Cheshire, U.K.
| | - Tamara Romero
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - Duncan E. Scott
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - David Winpenny
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - James Duce
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - John Skidmore
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - Jonathan H. Clarke
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
| | - Stephen P. Andrews
- The
ALBORADA Drug Discovery Institute, University
of Cambridge, Island Research Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0AH, U.K.
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5
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Mujalli A, Chicanne G, Bertrand-Michel J, Viars F, Stephens L, Hawkins P, Viaud J, Gaits-Iacovoni F, Severin S, Gratacap MP, Terrisse AD, Payrastre B. Profiling of phosphoinositide molecular species in human and mouse platelets identifies new species increasing following stimulation. Biochim Biophys Acta Mol Cell Biol Lipids 2018; 1863:1121-1131. [PMID: 29902570 DOI: 10.1016/j.bbalip.2018.06.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2018] [Revised: 05/15/2018] [Accepted: 06/10/2018] [Indexed: 12/17/2022]
Abstract
Phosphoinositides are bioactive lipids essential in the regulation of cell signaling as well as cytoskeleton and membrane dynamics. Their metabolism is highly active in blood platelets where they play a critical role during activation, at least through two well identified pathways involving phospholipase C and phosphoinositide 3-kinases (PI3K). Here, using a sensitive high-performance liquid chromatography-mass spectrometry method recently developed, we monitored for the first time the profiling of phosphatidylinositol (PI), PIP, PIP2 and PIP3 molecular species (fatty-acyl profiles) in human and mouse platelets during the course of stimulation by thrombin and collagen-related peptide. Furthermore, using class IA PI3K p110α or p110β deficient mouse platelets and a pharmacological inhibitor, we show the crucial role of p110β and the more subtle role of p110α in the production of PIP3 molecular species following stimulation. This comprehensive platelet phosphoinositides profiling provides important resources for future studies and reveals new information on phosphoinositides biology, similarities and differences in mouse and human platelets and unexpected dramatic increase in low-abundance molecular species of PIP2 during stimulation, opening new perspectives in phosphoinositide signaling in platelets.
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Affiliation(s)
| | - Gaëtan Chicanne
- INSERM U1048, I2MC, Université Paul Sabatier, 31432 Toulouse, France
| | - Justine Bertrand-Michel
- MetaToul-Lipidomic Core Facility, MetaboHUB, INSERM UMR-1048, Université Paul Sabatier, 31432 Toulouse, France
| | - Fanny Viars
- MetaToul-Lipidomic Core Facility, MetaboHUB, INSERM UMR-1048, Université Paul Sabatier, 31432 Toulouse, France
| | - Len Stephens
- Signalling Programme, Babraham Institute, Cambridge, United Kingdom
| | - Phil Hawkins
- Signalling Programme, Babraham Institute, Cambridge, United Kingdom
| | - Julien Viaud
- INSERM U1048, I2MC, Université Paul Sabatier, 31432 Toulouse, France
| | | | - Sonia Severin
- INSERM U1048, I2MC, Université Paul Sabatier, 31432 Toulouse, France
| | | | | | - Bernard Payrastre
- INSERM U1048, I2MC, Université Paul Sabatier, 31432 Toulouse, France; CHU de Toulouse, Laboratoire d'Hématologie, 31059 Toulouse Cedex 03, France.
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6
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Synergistic activation of G protein-gated inwardly rectifying potassium channels by cholesterol and PI(4,5)P 2. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1859:1233-1241. [PMID: 28377218 DOI: 10.1016/j.bbamem.2017.03.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 03/16/2017] [Accepted: 03/31/2017] [Indexed: 11/23/2022]
Abstract
G-protein gated inwardly rectifying potassium (GIRK or Kir3) channels play a major role in the control of the heart rate, and require the membrane phospholipid phosphatidylinositol-bis-phosphate (PI(4,5)P2) for activation. Recently, we have shown that the activity of the heterotetrameric Kir3.1/Kir3.4 channel that underlies atrial KACh currents was enhanced by cholesterol. Similarly, the activities of both the Kir3.4 homomer and its active pore mutant Kir3.4* (Kir3.4_S143T) were also enhanced by cholesterol. Here we employ planar lipid bilayers to investigate the crosstalk between PI(4,5)P2 and cholesterol, and demonstrate that these two lipids act synergistically to activate Kir3.4* currents. Further studies using the Xenopus oocytes heterologous expression system suggest that PI(4,5)P2 and cholesterol act via distinct binding sites. Whereas PI(4,5)P2 binds to the cytosolic domain of the channel, the putative binding region of cholesterol is located at the center of the transmembrane domain overlapping the central glycine hinge region of the channel. Together, our data suggest that changes in the levels of two key membrane lipids - cholesterol and PI(4,5)P2 - could act in concert to provide fine-tuning of Kir3 channel function.
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7
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Eag1 K + Channel: Endogenous Regulation and Functions in Nervous System. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2017; 2017:7371010. [PMID: 28367272 PMCID: PMC5358448 DOI: 10.1155/2017/7371010] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/27/2016] [Accepted: 01/31/2017] [Indexed: 02/04/2023]
Abstract
Ether-à-go-go1 (Eag1, Kv10.1, KCNH1) K+ channel is a member of the voltage-gated K+ channel family mainly distributed in the central nervous system and cancer cells. Like other types of voltage-gated K+ channels, the EAG1 channels are regulated by a variety of endogenous signals including reactive oxygen species, rendering the EAG1 to be in the redox-regulated ion channel family. The role of EAG1 channels in tumor development and its therapeutic significance have been well established. Meanwhile, the importance of hEAG1 channels in the nervous system is now increasingly appreciated. The present review will focus on the recent progress on the channel regulation by endogenous signals and the potential functions of EAG1 channels in normal neuronal signaling as well as neurological diseases.
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8
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Inhibitory potential of flavonoids on PtdIns(3,4,5)P3 binding with the phosphoinositide-dependent kinase 1 pleckstrin homology domain. Bioorg Med Chem Lett 2017; 27:420-426. [DOI: 10.1016/j.bmcl.2016.12.051] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2016] [Revised: 11/24/2016] [Accepted: 12/20/2016] [Indexed: 11/20/2022]
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9
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Kolay S, Basu U, Raghu P. Control of diverse subcellular processes by a single multi-functional lipid phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2]. Biochem J 2016; 473:1681-92. [PMID: 27288030 PMCID: PMC6609453 DOI: 10.1042/bcj20160069] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2016] [Accepted: 03/07/2016] [Indexed: 12/16/2022]
Abstract
Phosphatidylinositol 4,5-bisphosphate [PI(4,5)P2] is a multi-functional lipid that regulates several essential subcellular processes in eukaryotic cells. In addition to its well-established function as a substrate for receptor-activated signalling at the plasma membrane (PM), it is now recognized that distinct PI(4,5)P2 pools are present at other organelle membranes. However, a long-standing question that remains unresolved is the mechanism by which a single lipid species, with an invariant functional head group, delivers numerous functions without loss of fidelity. In the present review, we summarize studies that have examined the molecular processes that shape the repertoire of PI(4,5)P2 pools in diverse eukaryotes. Collectively, these studies indicate a conserved role for lipid kinase isoforms in generating functionally distinct pools of PI(4,5)P2 in diverse metazoan species. The sophistication underlying the regulation of multiple functions by PI(4,5)P2 is also shaped by mechanisms that regulate its availability to enzymes involved in its metabolism as well as molecular processes that control its diffusion at nanoscales in the PM. Collectively, these mechanisms ensure the specificity of PI(4,5)P2 mediated signalling at eukaryotic membranes.
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Affiliation(s)
- Sourav Kolay
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India Manipal University, Madhav Nagar, Manipal 576104, Karnataka, India
| | - Urbashi Basu
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
| | - Padinjat Raghu
- National Centre for Biological Sciences, TIFR-GKVK Campus, Bellary Road, Bangalore 560065, India
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10
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Human EAG channels are directly modulated by PIP2 as revealed by electrophysiological and optical interference investigations. Sci Rep 2016; 6:23417. [PMID: 27005320 PMCID: PMC4804213 DOI: 10.1038/srep23417] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2015] [Accepted: 03/03/2016] [Indexed: 11/28/2022] Open
Abstract
Voltage-gated ether à go-go (EAG) K+ channels are expressed in various types of cancer cells and also in the central nervous system. Aberrant overactivation of human EAG1 (hEAG1) channels is associated with cancer and neuronal disorders such as Zimmermann-Laband and Temple-Baraitser syndromes. Although hEAG1 channels are recognized as potential therapeutic targets, regulation of their functional properties is only poorly understood. Here, we show that the membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2) is a potent inhibitory gating modifier of hEAG1 channels. PIP2 inhibits the channel activity by directly binding to a short N-terminal segment of the channel important for Ca2+/calmodulin (CaM) binding as evidenced by bio-layer interferometry measurements. Conversely, depletion of endogenous PIP2 either by serotonin-induced phospholipase C (PLC) activation or by a rapamycin-induced translocation system enhances the channel activity at physiological membrane potentials, suggesting that PIP2 exerts a tonic inhibitory influence. Our study, combining electrophysiological and direct binding assays, demonstrates that hEAG1 channels are subject to potent inhibitory modulation by multiple phospholipids and suggests that manipulations of the PIP2 signaling pathway may represent a strategy to treat hEAG1 channel-associated diseases.
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11
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Adjobo-Hermans MJW, Cluitmans JCA, Bosman GJCGM. Neuroacanthocytosis: Observations, Theories and Perspectives on the Origin and Significance of Acanthocytes. TREMOR AND OTHER HYPERKINETIC MOVEMENTS (NEW YORK, N.Y.) 2015; 5:328. [PMID: 26317043 PMCID: PMC4548760 DOI: 10.7916/d8vh5n2m] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Subscribe] [Scholar Register] [Received: 05/28/2015] [Accepted: 07/31/2015] [Indexed: 12/12/2022]
Abstract
The presence of acanthocytes in the blood is characteristic of patients suffering from neuroacanthocytosis (NA). Recent studies have described abnormal phosphorylation of the proteins involved in connecting the membrane and cytoskeleton in patient-derived erythrocytes. The involvement of lipids in the underlying signaling pathways and recent reports on in vitro disease-associated lipid alterations support renewed research into lipid composition, signal transduction, and metabolism in patient erythrocytes. In addition to morphology, changes in membrane organization affect erythrocyte function and survival. Patient erythrocytes may have a decreased ability to deform, and this may contribute to accelerated erythrocyte removal and a decreased oxygen supply, especially in vulnerable brain regions. The presently available data indicate that acanthocytes are likely to originate in the bone marrow, making erythropoiesis an obvious new focus in NA research. Moreover, new, detailed morphological observations indicate that acanthocytes may be the tip of the iceberg with regard to misshapen erythrocytes in the circulation of patients with NA. A systematic assessment of patient erythrocyte morphology, deformability, oxygen delivery, and metabolism will be instrumental in determining the putative contribution of erythrocyte function to NA clinical symptoms.
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Affiliation(s)
- Merel J W Adjobo-Hermans
- Department of Biochemistry, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Judith C A Cluitmans
- Department of Biochemistry, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
| | - Giel J C G M Bosman
- Department of Biochemistry, Radboud University Medical Center, Radboud Institute for Molecular Life Sciences, Nijmegen, The Netherlands
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12
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Choi S, Thapa N, Tan X, Hedman AC, Anderson RA. PIP kinases define PI4,5P₂signaling specificity by association with effectors. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1851:711-23. [PMID: 25617736 PMCID: PMC4380618 DOI: 10.1016/j.bbalip.2015.01.009] [Citation(s) in RCA: 58] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2014] [Revised: 01/14/2015] [Accepted: 01/16/2015] [Indexed: 12/21/2022]
Abstract
Phosphatidylinositol 4,5-bisphosphate (PI4,5P₂) is an essential lipid messenger with roles in all eukaryotes and most aspects of human physiology. By controlling the targeting and activity of its effectors, PI4,5P₂modulates processes, such as cell migration, vesicular trafficking, cellular morphogenesis, signaling and gene expression. In cells, PI4,5P₂has a much higher concentration than other phosphoinositide species and its total content is largely unchanged in response to extracellular stimuli. The discovery of a vast array of PI4,5P₂ binding proteins is consistent with data showing that the majority of cellular PI4,5P₂is sequestered. This supports a mechanism where PI4,5P₂functions as a localized and highly specific messenger. Further support of this mechanism comes from the de novo synthesis of PI4,5P₂which is often linked with PIP kinase interaction with PI4,5P₂effectors and is a mechanism to define specificity of PI4,5P₂signaling. The association of PI4,5P₂-generating enzymes with PI4,5P₂effectors regulate effector function both temporally and spatially in cells. In this review, the PI4,5P₂effectors whose functions are tightly regulated by associations with PI4,5P₂-generating enzymes will be discussed. This article is part of a Special Issue entitled Phosphoinositides.
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Affiliation(s)
- Suyong Choi
- Cellular and Molecular Biology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Narendra Thapa
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Xiaojun Tan
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Andrew C Hedman
- Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA
| | - Richard A Anderson
- Cellular and Molecular Biology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA; Molecular and Cellular Pharmacology Program, University of Wisconsin-Madison, School of Medicine and Public Health, 1300 University Avenue, Madison, WI 53706, USA.
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13
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Le OTT, Nguyen TTN, Lee SY. Phosphoinositide turnover in Toll-like receptor signaling and trafficking. BMB Rep 2015; 47:361-8. [PMID: 24856829 PMCID: PMC4163850 DOI: 10.5483/bmbrep.2014.47.7.088] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2014] [Indexed: 12/29/2022] Open
Abstract
Lipid components in biological membranes are essential for maintaining cellular function. Phosphoinositides, the phosphorylated derivatives of phosphatidylinositol (PI), regulate many critical cell processes involving membrane signaling, trafficking, and reorganization. Multiple metabolic pathways including phosphoinositide kinases and phosphatases and phospholipases tightly control spatio-temporal concentration of membrane phosphoinositides. Metabolizing enzymes responsible for PI 4,5-bisphosphate (PI(4,5)P2) production or degradation play a regulatory role in Toll-like receptor (TLR) signaling and trafficking. These enzymes include PI 4-phosphate 5-kinase, phosphatase and tensin homolog, PI 3-kinase, and phospholipase C. PI(4,5)P2 mediates the interaction with target cytosolic proteins to induce their membrane translocation, regulate vesicular trafficking, and serve as a precursor for other signaling lipids. TLR activation is important for the innate immune response and is implicated in diverse pathophysiological disorders. TLR signaling is controlled by specific interactions with distinct signaling and sorting adaptors. Importantly, TLR signaling machinery is differentially formed depending on a specific membrane compartment during signaling cascades. Although detailed mechanisms remain to be fully clarified, phosphoinositide metabolism is promising for a better understanding of such spatio-temporal regulation of TLR signaling and trafficking. [BMB Reports 2014; 47(7): 361-368]
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Affiliation(s)
- Oanh Thi Tu Le
- Neuroscience Graduate Program, Department of Biomedical Sciences, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi 443-721, Korea
| | - Tu Thi Ngoc Nguyen
- Neuroscience Graduate Program, Department of Biomedical Sciences, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi 443-721, Korea
| | - Sang Yoon Lee
- Neuroscience Graduate Program, Department of Biomedical Sciences, and Chronic Inflammatory Disease Research Center, Ajou University School of Medicine, Suwon, Gyeonggi 443-721, Korea
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14
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Mori MX, Inoue R. New experimental trends for phosphoinositides research on ion transporter/channel regulation. J Pharmacol Sci 2014; 126:186-97. [PMID: 25367262 DOI: 10.1254/jphs.14r14cp] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Phosphoinositides(4,5)-bisphosphates [PI(4,5)P2] critically controls membrane excitability, the disruption of which leads to pathophysiological states. PI(4,5)P2 plays a primary role in regulating the conduction and gating properties of ion channels/transporters, through electrostatic and hydrophobic interactions that allow direct associations. In recent years, the development of many molecular tools have brought deep insights into the mechanisms underlying PI(4,5)P2-mediated regulation. This review summarizes the methods currently available to manipulate the cell membrane PI(4,5)P2 level including pharmacological interventions as well as newly designed molecular tools. We concisely introduce materials and experimental designs suitable for the study of PI(4,5)P2-mediated regulation of ion-conducting molecules, in order to assist researchers who are interested in this area. It is our further hope that the knowledge introduced in this review will help to promote our understanding about the pathology of diseases such as cardiac arrhythmias, bipolar disorders, and Alzheimer's disease which are somehow associated with a disruption of PI(4,5)P2 metabolism.
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Affiliation(s)
- Masayuki X Mori
- Department of Synthetic Chemistry and Biological Chemistry, School of Engineering, Kyoto University, Japan
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15
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Ueda Y. The Role of Phosphoinositides in Synapse Function. Mol Neurobiol 2014; 50:821-38. [DOI: 10.1007/s12035-014-8768-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2013] [Accepted: 06/01/2014] [Indexed: 11/30/2022]
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16
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Collaboration of AMPK and PKC to induce phosphorylation of Ser413 on PIP5K1B resulting in decreased kinase activity and reduced PtdIns(4,5)P2 synthesis in response to oxidative stress and energy restriction. Biochem J 2014; 455:347-58. [PMID: 23909401 DOI: 10.1042/bj20130259] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The spatial and temporal regulation of the second messenger PtdIns(4,5)P2 has been shown to be crucial for regulating numerous processes in the cytoplasm and in the nucleus. Three isoforms of PIP5K1 (phosphatidylinositol 4-phosphate 5-kinase), A, B and C, are responsible for the regulation of the major pools of cellular PtdIns(4,5)P2. PIP5K1B is negatively regulated in response to oxidative stress although it remains unclear which pathways regulate its activity. In the present study, we have investigated the regulation of PIP5K1B by protein phosphorylation. Using MS analysis, we identified 12 phosphorylation sites on PIP5K1B. We developed a phospho-specific antibody against Ser413 and showed that its phosphorylation was increased in response to treatment of cells with phorbol ester, H2O2 or energy restriction. Using inhibitors, we define a stress-dependent pathway that requires the activity of the cellular energy sensor AMPK (AMP-activated protein kinase) and PKC (protein kinase C) to regulate Ser413 phosphorylation. Furthermore, we demonstrate that PKC can directly phosphorylate Ser413 in vitro. Mutation of Ser413 to aspartate to mimic serine phosphorylation decreased both PIP5K1B activity in vitro and PtdIns(4,5)P2 synthesis in vivo. Our studies show that collaboration between AMPK and PKC dictates the extent of Ser413 phosphorylation on PIP5K1B and regulates PtdIns(4,5)P2 synthesis.
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Follo MY, Faenza I, Piazzi M, Blalock WL, Manzoli L, McCubrey JA, Cocco L. Nuclear PI-PLCβ1: an appraisal on targets and pathology. Adv Biol Regul 2013; 54:2-11. [PMID: 24296032 DOI: 10.1016/j.jbior.2013.11.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Accepted: 11/08/2013] [Indexed: 11/16/2022]
Abstract
Lipid signalling molecules are essential components of the processes that allow one extracellular signal to be transferred inside the nucleus, where specific lipid second messengers elicit reactions capable of regulating gene transcription, DNA replication or repair and DNA cleavage, eventually resulting in cell growth, differentiation, apoptosis or many other cell functions. Nuclear inositides are independently regulated, suggesting that the nucleus constitutes a functionally distinct compartment of inositol lipids metabolism. Indeed, nuclear inositol lipids themselves can modulate nuclear processes, such as transcription and pre-mRNA splicing, growth, proliferation, cell cycle regulation and differentiation. Nuclear PI-PLCβ1 is a key molecule for nuclear inositide signalling, where it plays a role in cell cycle progression, proliferation and differentiation. Here we review the targets and possible involvement of nuclear PI-PLCβ1 in human physiology and pathology.
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Affiliation(s)
- Matilde Y Follo
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy.
| | - Irene Faenza
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - Manuela Piazzi
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - William L Blalock
- CNR - Consiglio Nazionale delle Ricerche, Istituto di Genetica Molecolare and SC Laboratorio di Biologia Cellulare Muscoloscheletrica, IOR, Bologna, Italy
| | - Lucia Manzoli
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy
| | - James A McCubrey
- Department of Microbiology and Immunology, Brody School of Medicine at East Carolina University, Greenville, NC, USA
| | - Lucio Cocco
- Department of Biomedical and Neuromotor Sciences, Cellular Signalling Laboratory, University of Bologna, Via Irnerio 48, 40126 Bologna, Italy.
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18
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Shah ZH, Jones DR, Sommer L, Foulger R, Bultsma Y, D'Santos C, Divecha N. Nuclear phosphoinositides and their impact on nuclear functions. FEBS J 2013; 280:6295-310. [PMID: 24112514 DOI: 10.1111/febs.12543] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Revised: 09/11/2013] [Accepted: 09/16/2013] [Indexed: 12/23/2022]
Abstract
Polyphosphoinositides (PPIn) are important lipid molecules whose levels are de-regulated in human diseases such as cancer, neurodegenerative disorders and metabolic syndromes. PPIn are synthesized and degraded by an array of kinases, phosphatases and lipases which are localized to various subcellular compartments and are subject to regulation in response to both extra- and intracellular cues. Changes in the activities of enzymes that metabolize PPIn lead to changes in the profiles of PPIn in various subcellular compartments. Understanding how subcellular PPIn are regulated and how they affect downstream signaling is critical to understanding their roles in human diseases. PPIn are present in the nucleus, and their levels are changed in response to various stimuli, suggesting that they may serve to regulate specific nuclear functions. However, the lack of nuclear downstream targets has hindered the definition of which pathways nuclear PPIn affect. Over recent years, targeted and global proteomic studies have identified a plethora of potential PPIn-interacting proteins involved in many aspects of transcription, chromatin remodelling and mRNA maturation, suggesting that PPIn signalling within the nucleus represents a largely unexplored novel layer of complexity in the regulation of nuclear functions.
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Affiliation(s)
- Zahid H Shah
- Cancer Research UK Inositide Laboratory, Paterson Institute for Cancer Research, Manchester, UK
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19
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Keune WJ, Jones DR, Divecha N. PtdIns5P and Pin1 in oxidative stress signaling. Adv Biol Regul 2013; 53:179-189. [PMID: 23602596 DOI: 10.1016/j.jbior.2013.02.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Accepted: 02/21/2013] [Indexed: 06/02/2023]
Abstract
Oxidative signaling is important in cellular health, involved in aging and contributes to the development of several diseases such as cancer, neurodegeneration and diabetes. Correct management of reactive oxygen species (ROS) prevents oxidative stress within cells and is imperative for cellular wellbeing. A key pathway that is regulated by oxidative stress is the activation of proline-directed stress kinases (p38, JNK). Phosphorylation induced by these kinases is often translated into cellular outcome through the recruitment of the prolyl-isomerase Pin1. Pin1 binds to phosphorylated substrates using its WW-domain and can induce conformational changes in the target protein through its prolyl-isomerase activity. We show that exposure of cells to UV irradiation or hydrogen peroxide (H₂O₂), induces the synthesis of the phosphoinositide second messenger PtdIns5P in part by inducing the interaction between phosphatidylinositol-5-phosphate 4-kinase (PIP4K) enzymes that remove PtdIns5P, with Pin1. In response to H₂O₂ exposure, Murine Embryonic Fibroblasts (MEFs) derived from Pin1⁻/⁻ mice showed increased cell viability and an increased abundance of PtdIns5P compared to wild-type MEFs. Decreasing the levels of PtdIns5P in Pin1⁻/⁻ MEFs decreased both their viability in response to H₂O₂ exposure and the expression of genes required for cellular ROS management. The decrease in the expression of these genes manifested itself in the increased accumulation of cellular ROS. These data strongly argue that PtdIns5P acts as a stress-induced second messenger that can calibrate how cells manage ROS.
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Affiliation(s)
- Willem-Jan Keune
- Inositide Laboratory CRUK, The Paterson Institute for Cancer Research, University of Manchester, Manchester M20 4BX, United Kingdom.
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20
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Keune WJ, Jones DR, Bultsma Y, Sommer L, Zhou XZ, Lu KP, Divecha N. Regulation of phosphatidylinositol-5-phosphate signaling by Pin1 determines sensitivity to oxidative stress. Sci Signal 2012. [PMID: 23193159 DOI: 10.1126/scisignal.2003223] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Oxidative signaling and oxidative stress contribute to aging, cancer, and diseases resulting from neurodegeneration. Pin1 is a proline isomerase that recognizes phosphorylated substrates and regulates the localization and conformation of its targets. Pin1(-/-) mice show phenotypes associated with premature aging, yet mouse embryonic fibroblasts (MEFs) from these mice are resistant to hydrogen peroxide (H(2)O(2))-induced cell death. We found that the abundance of phosphatidylinositol-5-phosphate (PtdIns5P) was increased in response to H(2)O(2), an effect that was enhanced in Pin1(-/-) MEFs. Reduction of H(2)O(2)-induced PtdIns5P compromised cell viability in response to oxidative stress, suggesting that PtdIns5P contributed to the enhanced cell viability of Pin1(-/-) MEFs exposed to oxidative stress. The increased PtdIns5P in the Pin1(-/-) MEFs stimulated the expression of genes involved in defense against oxidative stress and reduced the accumulation of reactive oxygen species. Pin1 and PtdIns5P 4-kinases (PIP4Ks), enzymes that phosphorylate and thereby reduce the amount of PtdIns5P, interacted in a manner dependent on the phosphorylation of PIP4K. Although reintroduction of Pin1 into the Pin1(-/-) MEFs reduced the amount of PtdIns5P produced in response to H(2)O(2), in vitro assays indicated that the isomerase activity of Pin1 inhibited PIP4K activity. Whether this isomerise-mediated inhibition of PIP4K occurs in cells remains an open question, but the data suggest that the regulation of PIP4K by Pin1 may be complex.
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Affiliation(s)
- Willem-Jan Keune
- CRUK Inositide Laboratory, Paterson Institute for Cancer Research, The University of Manchester, Manchester M20 4BX, UK
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21
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Abstract
Phosphoinositides (PIs) are minor components of cellular membranes that play critical regulatory roles in several intracellular functions. This chapter describes the main enzymes regulating the turnover of each of the seven PIs in mammalian cells and introduces to some of their intracellular functions and to some evidences of their involvement in human diseases. Due to the complex interrelation between the distinct PIs and the plethora of functions that they can regulate inside a cell, this chapter is not meant to be a comprehensive coverage of all aspects of PI signalling but rather an introduction to this complex signalling field. For more details of their regulation/functions and extensive description of their intracellular roles, more detailed reviews are suggested on each single topic.
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Affiliation(s)
- Tania Maffucci
- Centre for Diabetes, Blizard Institute, Inositide Signalling Group, Queen Mary University of London, Barts and The London School of Medicine and Dentistry, UK.
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22
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Clarke JH, Irvine RF. The activity, evolution and association of phosphatidylinositol 5-phosphate 4-kinases. Adv Biol Regul 2012; 52:40-45. [PMID: 21945524 DOI: 10.1016/j.advenzreg.2011.09.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 09/05/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Jonathan H Clarke
- Department of Pharmacology, Tennis Court Road, Cambridge CB2 1PD, UK
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23
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Rosenhouse‐Dantsker A, Mehta D, Levitan I. Regulation of Ion Channels by Membrane Lipids. Compr Physiol 2012; 2:31-68. [DOI: 10.1002/cphy.c110001] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
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24
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The inositol Inpp5k 5-phosphatase affects osmoregulation through the vasopressin-aquaporin 2 pathway in the collecting system. Pflugers Arch 2011; 462:871-83. [DOI: 10.1007/s00424-011-1028-0] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2011] [Revised: 09/04/2011] [Accepted: 09/05/2011] [Indexed: 01/15/2023]
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25
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Kinase associated-1 domains drive MARK/PAR1 kinases to membrane targets by binding acidic phospholipids. Cell 2011; 143:966-77. [PMID: 21145462 DOI: 10.1016/j.cell.2010.11.028] [Citation(s) in RCA: 134] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2010] [Revised: 08/03/2010] [Accepted: 11/01/2010] [Indexed: 12/26/2022]
Abstract
Phospholipid-binding modules such as PH, C1, and C2 domains play crucial roles in location-dependent regulation of many protein kinases. Here, we identify the KA1 domain (kinase associated-1 domain), found at the C terminus of yeast septin-associated kinases (Kcc4p, Gin4p, and Hsl1p) and human MARK/PAR1 kinases, as a membrane association domain that binds acidic phospholipids. Membrane localization of isolated KA1 domains depends on phosphatidylserine. Using X-ray crystallography, we identified a structurally conserved binding site for anionic phospholipids in KA1 domains from Kcc4p and MARK1. Mutating this site impairs membrane association of both KA1 domains and intact proteins and reveals the importance of phosphatidylserine for bud neck localization of yeast Kcc4p. Our data suggest that KA1 domains contribute to "coincidence detection," allowing kinases to bind other regulators (such as septins) only at the membrane surface. These findings have important implications for understanding MARK/PAR1 kinases, which are implicated in Alzheimer's disease, cancer, and autism.
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26
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Lee SY, Kim B, Jeong HK, Min KJ, Liu T, Park JY, Joe EH, Jou I. Enhanced phosphatidylinositol 4-phosphate 5-kinase alpha expression and PI(4,5)P2 production in LPS-stimulated microglia. Neurochem Int 2010; 57:600-7. [PMID: 20659513 DOI: 10.1016/j.neuint.2010.07.008] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2010] [Revised: 06/23/2010] [Accepted: 07/19/2010] [Indexed: 01/01/2023]
Abstract
Microglia are the major glial cells responsible for immune responses against harmful substances in the central nervous system. Type I phosphatidylinositol 4-phosphate 5-kinase alpha (PIP5Kalpha) and its lipid product, phosphatidylinositol 4,5-bisphosphate (PI[4,5]P(2)), regulate important cell surface functions. Here, we report that lipopolysaccharide (LPS) significantly enhanced PIP5Kalpha mRNA and protein expression levels in a time- and concentration-dependent manner in microglia. Furthermore, LPS stimulation led to a robust increase in PI(4,5)P(2) in the plasma membrane, demonstrated by PI(4,5)P(2) immunostaining or PI(4,5)P(2) imaging using a PI(4,5)P(2)-specific probe, tubby (R332H), fused to yellow fluorescent protein. Phosphatidylinositol 3-kinase, p38 mitogen-activated protein kinase (MAPK), p42/44 MAPK, and c-Jun N-terminal kinase signaling pathway inhibitors clearly reduced PIP5Kalpha expression, indicating that these pathways are necessary for LPS-induced PIP5Kalpha expression. In addition, inhibition of nuclear factor-kappaB and Sp1 transcription factors interfered with the LPS-induced upregulation of PIP5Kalpha. Delivery of PI(4,5)P(2) into microglia increased the expression of interleukin-1beta and tumor necrosis factor alpha. These findings indicate that PIP5Kalpha upregulation and the subsequent rise in PI(4,5)P(2) in LPS-stimulated microglia may positively regulate microglial inflammatory responses.
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Affiliation(s)
- Sang Yoon Lee
- Neuroscience Graduate Program, Ajou University School of Medicine, Suwon, Gyeonggi, Republic of Korea.
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27
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Logothetis DE, Petrou VI, Adney SK, Mahajan R. Channelopathies linked to plasma membrane phosphoinositides. Pflugers Arch 2010; 460:321-41. [PMID: 20396900 PMCID: PMC4040125 DOI: 10.1007/s00424-010-0828-y] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2010] [Revised: 03/11/2010] [Accepted: 03/13/2010] [Indexed: 02/07/2023]
Abstract
The plasma membrane phosphoinositide phosphatidylinositol 4,5-bisphosphate (PIP2) controls the activity of most ion channels tested thus far through direct electrostatic interactions. Mutations in channel proteins that change their apparent affinity to PIP2 can lead to channelopathies. Given the fundamental role that membrane phosphoinositides play in regulating channel activity, it is surprising that only a small number of channelopathies have been linked to phosphoinositides. This review proposes that for channels whose activity is PIP2-dependent and for which mutations can lead to channelopathies, the possibility that the mutations alter channel-PIP2 interactions ought to be tested. Similarly, diseases that are linked to disorders of the phosphoinositide pathway result in altered PIP2 levels. In such cases, it is proposed that the possibility for a concomitant dysregulation of channel activity also ought to be tested. The ever-growing list of ion channels whose activity depends on interactions with PIP2 promises to provide a mechanism by which defects on either the channel protein or the phosphoinositide levels can lead to disease.
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Affiliation(s)
- Diomedes E Logothetis
- Department of Physiology and Biophysics, Virginia Commonwealth University, School of Medicine, Richmond, VA 23298, USA.
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28
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Gallicchio MA, Bach LA. Advanced glycation end products inhibit Na+ K+ ATPase in proximal tubule epithelial cells: role of cytosolic phospholipase A2alpha and phosphatidylinositol 4-phosphate 5-kinase gamma. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2010; 1803:919-30. [PMID: 20435073 DOI: 10.1016/j.bbamcr.2010.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2009] [Revised: 04/09/2010] [Accepted: 04/12/2010] [Indexed: 11/18/2022]
Abstract
Chronic hyperglycaemia during diabetes leads to non-enzymatic glycation of proteins to form advanced glycation end products (AGEs) that contribute to nephropathy. In diabetes, renal Na+ K+ ATPase (NKA) activity is downregulated and phosphoinositide metabolism is upregulated. We examined the effects of AGEs on NKA activity in porcine LLC-PK1 and human HK2 proximal tubule epithelial cells. AGE-BSA increased cellular phosphoinositol 4,5 bisphosphate (PIP2) production as determined by immunofluorescence microscopy and thin layer chromatography. AGE-BSA (40 microM) induced 3H-arachidonic acid release and reactive oxygen species (ROS) production via cytosolic phospholipase A2 (cPLA2) activation. Within minutes, AGE-BSA significantly inhibited NKA surface expression and activity in a dose- and time-dependent manner as determined by immunofluorescence staining and [86Rb+] uptake, respectively, suggesting AGEs inhibit NKA by stimulating its endocytosis. The AGE-BSA-induced decrease in cell surface NKA was reversed by a cPLA2alpha inhibitor, neomycin, a PIP2 inhibitor, and PP2, a Src inhibitor. AGE-BSA increased binding of NKA to the alpha-adaptin but not beta2- or mu2-adaptin subunits of the AP-2 clathrin pit adaptor complex. Transfection of HK2 cells with PIP5Kgamma siRNA prevented AGE-BSA inhibition of NKA activity. AGEs may stimulate PIP5Kgamma to increase PIP2 production, which may enhance AP-2 localisation to clathrin pits, increase clathrin pit formation, enhance NKA cargo recognition by AP-2 and/or stimulate cPLA2alpha activity. These results suggest AGEs modulate arachidonic acid and phosphoinositide metabolism to inhibit NKA via clathrin-mediated endocytosis. Elucidation of new intracellular AGE signaling pathways may lead to improved therapies for diabetic nephropathy.
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Affiliation(s)
- Marisa A Gallicchio
- Monash University, Department of Medicine, Alfred Hospital, Commercial Rd., Prahran, 3004, Australia
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29
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Ogiso H, Nakamura K, Yatomi Y, Shimizu T, Taguchi R. Liquid chromatography/mass spectrometry analysis revealing preferential occurrence of non-arachidonate-containing phosphatidylinositol bisphosphate species in nuclei and changes in their levels during cell cycle. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:436-442. [PMID: 20069690 DOI: 10.1002/rcm.4415] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Phosphatidylinositol phosphates (PtdInsPs) are present within the nucleus, as well as in the membrane. In this mass spectrometry study, different acyl-containing species of endonuclear PtdInsPs were analyzed in order to clearly understand the role of individual molecular species. A (34:1) acyl-containing phosphatidylinositol bisphosphate [PtdInsP(2)(34:1)] and PtdInsP(2)(36:1) were preferentially detected in envelope-less nuclei prepared from various cultured human cells, while PtdInsP(2)(38:4) was not a major component within these nuclei. A significant amount of PtdInsP(2)(34:0) was detected in the HeLa cell nucleus, but not in the A431 and THP-1 cell nuclei. During the cell cycle in HeLa cells, PtdInsP(2)(34:0) levels increased in the early G1 phase, and then gradually decreased through S phase, while PtdInsP(2)(34:1) levels tended to decrease only in late G1 phase and PtdInsP(2)(38:4) did not change significantly. Thus, individual PtdInsP(2) species apparently play different roles in nuclear events based on individual regulation of endonuclear levels. The non-arachidonate-containing species were also detected in normal human blood and fluids, suggesting that these minor species may have unique functions in the human body. The techniques used in this study will be applied to clinical studies on a PtdInsPs metabolism.
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Affiliation(s)
- Hideo Ogiso
- Department of Metabolome, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo 113-0033, Japan.
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Clarke JH, Emson PC, Irvine RF. Distribution and neuronal expression of phosphatidylinositol phosphate kinase IIgamma in the mouse brain. J Comp Neurol 2010; 517:296-312. [PMID: 19757494 PMCID: PMC2814081 DOI: 10.1002/cne.22161] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The role of cellular phosphatidylinositol 5-phosphate (PtdIns5P), as a signalling molecule or as a substrate for the production of small, compartmentalized pools of phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P2], may be dependent on cell type and subcellular localization. PtdIns5P levels are primarily regulated by the PtdIns5P 4-kinases (type II PIP kinases or PIP4Ks), and we have investigated the expression and localization in the brain of the least-studied PIP4K isoform, PIP4Kγ. In situ hybridization and immunohistochemistry, using antisense oligonucleotide probes and a PIP4Kγ-specific antibody, revealed that this isoform has a restricted CNS expression profile. The use of antibodies to different cell markers showed that this expression is limited to neurons, particularly the cerebellar Purkinje cells, pyramidal cells of the hippocampus, large neuronal cell types in the cerebral cortex including pyramidal cells, and mitral cells in the olfactory bulb and is not expressed in cerebellar, hippocampal formation, or olfactory bulb granule cells. In neurons expressing this enzyme, PIP4Kγ has a vesicular distribution and shows partial colocalization with markers of cellular compartments of the endomembrane trafficking pathway. The PIP4Kγ isoform expression is established after day 7 of postnatal development. Overall, our data suggest that PIP4Kγ may have a role in neuron function, specifically in the regulation of vesicular transport, in specific regions of the developed brain. J. Comp. Neurol. 517:296–312, 2009. © 2009 Wiley-Liss, Inc.
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Affiliation(s)
- Jonathan H Clarke
- Department of Pharmacology, University of Cambridge, Tennis Court Road, Cambridge, CB2 1PD United Kingdom.
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Perez-Burgos A, Prieto G, Galarraga E, Bargas J. CaV2.1 channels are modulated by muscarinic M1 receptors through phosphoinositide hydrolysis in neostriatal neurons. Neuroscience 2010; 165:293-9. [DOI: 10.1016/j.neuroscience.2009.10.056] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2009] [Revised: 10/24/2009] [Accepted: 10/22/2009] [Indexed: 11/30/2022]
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Zhu W, Trivedi CM, Zhou D, Yuan L, Lu MM, Epstein JA. Inpp5f is a polyphosphoinositide phosphatase that regulates cardiac hypertrophic responsiveness. Circ Res 2009; 105:1240-7. [PMID: 19875726 DOI: 10.1161/circresaha.109.208785] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Cardiac hypertrophy occurs in response to a variety of extrinsic and intrinsic stimuli that impose increased biomechanical stress. The phosphatidylinositol 3-kinase (PI3K)/Akt pathway has previously been strongly associated with hypertrophic signaling in the heart, and with the control of cell size in multiple contexts. This pathway is tightly regulated by many factors, including a host of kinases and phosphatases that function at multiple steps in the signaling cascade. For example, the PTEN (phosphatase and tensin homolog) tumor suppressor protein is a phosphoinositide 3-phosphatase that, by metabolizing phosphatidylinositol 3,4,5-trisphosphate (PtdIns[3,4,5]P(3), PIP3), acts in direct antagonism to growth factor-stimulated PI3K. Inhibition of PTEN leads to cardiomyocyte hypertrophy. Another polyphoinositide phosphatase, inositol polyphosphate-5-phosphatase F (Inpp5f) has recently been implicated in regulation of cardiac hypertrophy. Like PTEN, this phosphatase can degrade PtdIns(3,4,5)P(3) and thus modulates the PI3K/Akt pathway. OBJECTIVE To characterize the role of Inpp5f in regulating cardiac hypertrophy. METHODS AND RESULTS We generated homozygous Inpp5f knockout mice and cardiac specific Inpp5f overexpression transgenic mice. We evaluated their hearts for biochemical, structural and functional changes. Inpp5f knockout mice have augmented hypertrophy and reactivation of the fetal gene program in response to stress when compared to wild-type littermates. Furthermore, cardiac overexpression of Inpp5f in transgenic mice reduces hypertrophic responsiveness. CONCLUSIONS Our results suggest that Inpp5f is a functionally important endogenous modulator of cardiac myocyte size and of the cardiac response to stress.
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Affiliation(s)
- Wenting Zhu
- 1154 BRB II, University of Pennsylvania, 421 Curie Blvd, Philadelphia PA 19104.
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GERILECHAOGETU, HANIEH H, ABE A, KONDO Y. Extracellular signal-regulated kinase (ERK) activation in chicken heterophils stimulated with phorbol 12-myristate 13-acetate (PMA), Formyl-methionylleucyl-phenylalanine (fMLP) and lipopolysaccharide (LPS). Anim Sci J 2009; 80:577-84. [DOI: 10.1111/j.1740-0929.2009.00674.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Investigation of the H+–myo-inositol transporter (HMIT) as a neuronal regulator of phosphoinositide signalling. Biochem Soc Trans 2009; 37:1139-43. [DOI: 10.1042/bst0371139] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Phosphoinositide signalling regulates a series of important neuronal processes that are thought to be altered in mood disorders. Furthermore, mood-stabilizing drugs inhibit key enzymes that regulate phosphoinositide production and alter neuronal growth cone morphology in an inositol-reversible manner. Inositol is taken up by neurons from the extracellular fluid, presumably via membrane transporters; it can also be synthesized by the enzyme MIP-synthase (myo-inositol-1-phosphate synthase) and, in addition, it is generated by inositol phospholipid hydrolysis. The neuronal-specific HMIT (H+–myo-inositol transporter) represents a potential regulator of inositol signalling in neurons that warrants further investigation.
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Demian DJ, Clugston SL, Foster MM, Rameh L, Sarkes D, Townson SA, Yang L, Zhang M, Charlton ME. High-throughput, cell-free, liposome-based approach for assessing in vitro activity of lipid kinases. ACTA ACUST UNITED AC 2009; 14:838-44. [PMID: 19641220 DOI: 10.1177/1087057109339205] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Lipid kinases are central players in lipid signaling pathways involved in inflammation, tumorigenesis, and metabolic syndrome. A number of these kinase targets have proven difficult to investigate in higher throughput cell-free assay systems. This challenge is partially due to specific substrate interaction requirements for several of the lipid kinase family members and the resulting incompatibility of these substrates with most established, homogeneous assay formats. Traditional, cell-free in vitro investigational methods for members of the lipid kinase family typically involve substrate incorporation of [gamma-32P] and resolution of signal by thin-layer chromatography (TLC) and autoradiograph densitometry. This approach, although highly sensitive, does not lend itself to high-throughput testing of large numbers of small molecules (100 s to 1 MM+). The authors present the development and implementation of a fully synthetic, liposome-based assay for assessing in vitro activity of phosphatidylinositol-5-phosphate-4-kinase isoforms (PIP4KIIbeta and alpha) in 2 commonly used homogeneous technologies. They have validated these assays through compound testing in both traditional TLC and radioactive filterplate approaches as well as binding validation using isothermic calorimetry. A directed library representing known kinase pharmacophores was screened against type IIbeta phosphatidylinositol-phosphate kinase (PIPK) to identify small-molecule inhibitors. This assay system can be applied to other types and isoforms of PIPKs as well as a variety of other lipid kinase targets.
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Affiliation(s)
- Douglas J Demian
- Research Technology Center, Pfizer, Inc., Cambridge, Massachusetts 02139, USA
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Proteomic studies of a single CNS synapse type: the parallel fiber/purkinje cell synapse. PLoS Biol 2009; 7:e83. [PMID: 19402746 PMCID: PMC2672601 DOI: 10.1371/journal.pbio.1000083] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2008] [Accepted: 03/02/2009] [Indexed: 01/04/2023] Open
Abstract
Precise neuronal networks underlie normal brain function and require distinct classes of synaptic connections. Although it has been shown that certain individual proteins can localize to different classes of synapses, the biochemical composition of specific synapse types is not known. Here, we have used a combination of genetically engineered mice, affinity purification, and mass spectrometry to profile proteins at parallel fiber/Purkinje cell synapses. We identify approximately 60 candidate postsynaptic proteins that can be classified into 11 functional categories. Proteins involved in phospholipid metabolism and signaling, such as the protein kinase MRCKgamma, are major unrecognized components of this synapse type. We demonstrate that MRCKgamma can modulate maturation of dendritic spines in cultured cortical neurons, and that it is localized specifically to parallel fiber/Purkinje cell synapses in vivo. Our data identify a novel synapse-specific signaling pathway, and provide an approach for detailed investigations of the biochemical complexity of central nervous system synapse types.
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Great expectations for PIP: phosphoinositides as regulators of signaling during development and disease. Dev Cell 2009; 16:12-20. [PMID: 19154715 DOI: 10.1016/j.devcel.2008.12.006] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Phosphoinositides function as signaling precursors as well as regulators and scaffolds of signaling molecules required for important cellular processes such as membrane trafficking. Although a picture of the biochemical and cell biological functions of phosphoinositides is emerging, less is known about how these functions impact signaling on a broader scale during development. This review summarizes recent work on the role of phosphoinositides in developmental signaling and in a number of diseases and developmental disorders.
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Kim HJ, Thayer SA. Lithium increases synapse formation between hippocampal neurons by depleting phosphoinositides. Mol Pharmacol 2009; 75:1021-30. [PMID: 19188338 DOI: 10.1124/mol.108.052357] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The mood-stabilizing effects of lithium are well documented, although its mechanism of action remains unknown. Increases in gray matter volume detected in patients with bipolar disorder who were treated with lithium suggest that changes in the number of synapses might underlie its therapeutic effects. We investigated the effects of lithium on the number of synaptic connections between hippocampal neurons in culture. Confocal imaging of neurons expressing postsynaptic density protein 95 fused to green fluorescent protein (PSD95-GFP) enabled visualization of synaptic sites. PSD95-GFP fluorescent puncta represented functional synapses, and lithium (4 h, 5 mM) increased their number by 150 +/- 12%. The increase was time- and concentration-dependent (EC(50) = 1.0 +/- 0.6 mM). Lithium induced a parallel increase in the presynaptic marker synaptophysin-GFP. Valproic acid, another mood stabilizer, also increased the number of fluorescent puncta at a clinically relevant concentration. Inhibition of postsynaptic glutamate receptors or presynaptic inhibition of neurotransmitter release significantly reduced lithium-induced synapse formation, indicating that glutamatergic synaptic transmission was required. Pretreatment with exogenous myo-inositol inhibited synapse formation, demonstrating that depletion of inositol was necessary to increase synaptic connections. In contrast, inhibition of glycogen synthase kinase 3beta did not mimic lithium-induced synapse formation. Pharmacological and lipid reconstitution experiments showed that new synapses formed as a result of depletion of phosphatidylinositol-4-phosphate rather than a build-up of polyphosphoinositides or changes in the activity of phospholipase C, protein kinase C, or phosphatidylinositol-3-kinase. Increased synaptic connections may underlie the mood-stabilizing effects of lithium in patients with bipolar disorder and could contribute to the convulsions produced by excessive doses of this drug.
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Affiliation(s)
- Hee Jung Kim
- Department of Pharmacology, University of Minnesota Medical School, Minneapolis, MN 55455, USA
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Halstead JR, Snel MH, Meeuws S, Jones DR, Divecha N. Assaying endogenous phosphatidylinositol-4-phosphate 5-kinase (PIP5K) activities. Methods Mol Biol 2009; 462:391-402. [PMID: 19160683 DOI: 10.1007/978-1-60327-115-8_25] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Phosphoinositides are a family of lipid second messengers interlinked by an extensive and highly regulated network of kinases and phosphatases. The modulation of phosphoinositide profiles can regulate numerous cancer-related pathways, including cell survival, cell proliferation, migration, integrin activation, and transcription. PtdIns(4,5)P2 is at the heart of phosphoinositide signaling; its levels are controlled by enzymes that synthesize it and those that degrade it. Phosphatidylinositol-4-phosphate 5-kinases (PIP5 K) phosphorylate PtdIns4P on the 5-position and constitute the major pathway for the generation of PtdIns(4,5)P2. We will discuss how to suppress the expression of human PIP5 Kbeta using RNAi and how to measure the activity and levels of the endogenous enzyme. We describe a method to immunoprecipitate the endogenous PIP5 Kbeta and to assay its activity. Western blotting with another panel of antibodies is then used to determine the levels of endogenous PIP5 Kbeta in the immunoprecipitates.
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Affiliation(s)
- Jonathan R Halstead
- Division of Cellular Biochemistry, The Netherlands Cancer Institute, Amsterdam
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Martín‐Belmonte F, Rodríguez‐Fraticelli AE. Chapter 3 Acquisition of Membrane Polarity in Epithelial Tube Formation. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2009; 274:129-82. [DOI: 10.1016/s1937-6448(08)02003-0] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Sala G, Dituri F, Raimondi C, Previdi S, Maffucci T, Mazzoletti M, Rossi C, Iezzi M, Lattanzio R, Piantelli M, Iacobelli S, Broggini M, Falasca M. Phospholipase C 1 Is Required for Metastasis Development and Progression. Cancer Res 2008; 68:10187-96. [DOI: 10.1158/0008-5472.can-08-1181] [Citation(s) in RCA: 114] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Adjobo-Hermans MJW, Goedhart J, Gadella TWJ. Regulation of PLCβ1a membrane anchoring by its substrate phosphatidylinositol (4,5)-bisphosphate. J Cell Sci 2008; 121:3770-7. [DOI: 10.1242/jcs.029785] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Basic knowledge as to the subcellular location and dynamics of PLCβ isozymes is scant. Here, we report on the subcellular location of GFP-PLCβ1a and the use of total internal reflection fluorescence (TIRF) microscopy to examine the dynamics of GFP-PLCβ1a at the plasma membrane upon stimulation of Gq-coupled receptors. Using this technique, we observed PLCβ1a dissociation from the plasma membrane upon addition of agonist. An increase in intracellular calcium and a decrease in PtdIns(4,5)P2 both coincided with a translocation of PLCβ1a from the plasma membrane into the cytosol. In order to differentiate between calcium and PtdIns(4,5)P2, rapamycin-induced heterodimerization of FRB and FKBP12 fused to 5-phosphatase IV was used to instantaneously convert PtdIns(4,5)P2 into PtdIns(4)P. Addition of rapamycin caused PLCβ1a to dissociate from the plasma membrane, indicating that removal of PtdIns(4,5)P2 is sufficient to cause translocation of PLCβ1a from the plasma membrane. In conclusion, PLCβ1a localization is regulated by its own substrate.
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Affiliation(s)
- Merel J. W. Adjobo-Hermans
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, Centre for Advanced Microscopy, University of Amsterdam, Kruislaan 316, NL-1098 SM, Amsterdam, The Netherlands
| | - Joachim Goedhart
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, Centre for Advanced Microscopy, University of Amsterdam, Kruislaan 316, NL-1098 SM, Amsterdam, The Netherlands
| | - Theodorus W. J. Gadella
- Swammerdam Institute for Life Sciences, Section of Molecular Cytology, Centre for Advanced Microscopy, University of Amsterdam, Kruislaan 316, NL-1098 SM, Amsterdam, The Netherlands
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Transient receptor potential channels meet phosphoinositides. EMBO J 2008; 27:2809-16. [PMID: 18923420 PMCID: PMC2570475 DOI: 10.1038/emboj.2008.217] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2008] [Accepted: 09/23/2008] [Indexed: 11/08/2022] Open
Abstract
Transient receptor potential (TRP) cation channels are unique cellular sensors that are involved in multiple cellular functions, ranging from transduction of sensory signals to the regulation of Ca(2+) and Mg(2+) homoeostasis. Malfunctioning of TRP channels is now recognized as the cause of several hereditary and acquired human diseases. At the time of cloning of the first Drosophila TRP channel, a close connection between gating and phosphatidylinositol phosphates (PIPs) was already recognized. In this review, we summarize current knowledge about the mechanisms of interaction between TRP channels and PIPs, and discuss the possible functional implications of TRP-PIP interactions to human physiology and pathophysiology.
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Psychotropic drugs interfere with the tight coupling of polyphosphoinositide cycle metabolites in human platelets: A result of receptor-independent drug intercalation in the plasma membrane? BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:2165-76. [DOI: 10.1016/j.bbamem.2008.04.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/13/2008] [Revised: 04/16/2008] [Accepted: 04/21/2008] [Indexed: 11/19/2022]
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Synaptojanin 1-linked phosphoinositide dyshomeostasis and cognitive deficits in mouse models of Down's syndrome. Proc Natl Acad Sci U S A 2008; 105:9415-20. [PMID: 18591654 DOI: 10.1073/pnas.0803756105] [Citation(s) in RCA: 134] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Phosphatidylinositol-4,5-bisphosphate [PtdIns(4,5)P(2)] is a signaling phospholipid implicated in a wide variety of cellular functions. At synapses, where normal PtdIns(4,5)P(2) balance is required for proper neurotransmission, the phosphoinositide phosphatase synaptojanin 1 is a key regulator of its metabolism. The underlying gene, SYNJ1, maps to human chromosome 21 and is thus a candidate for involvement in Down's syndrome (DS), a complex disorder resulting from the overexpression of trisomic genes. Here, we show that PtdIns(4,5)P(2) metabolism is altered in the brain of Ts65Dn mice, the most commonly used model of DS. This defect is rescued by restoring Synj1 to disomy in Ts65Dn mice and is recapitulated in transgenic mice overexpressing Synj1 from BAC constructs. These transgenic mice also exhibit deficits in performance of the Morris water maze task, suggesting that PtdIns(4,5)P(2) dyshomeostasis caused by gene dosage imbalance for Synj1 may contribute to brain dysfunction and cognitive disabilities in DS.
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van Leeuwen W, Vermeer JEM, Gadella TWJ, Munnik T. Visualization of phosphatidylinositol 4,5-bisphosphate in the plasma membrane of suspension-cultured tobacco BY-2 cells and whole Arabidopsis seedlings. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2007; 52:1014-26. [PMID: 17908156 DOI: 10.1111/j.1365-313x.2007.03292.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
Phosphatidylinositol 4,5-bisphosphate [PtdIns(4,5)P(2)] is an important signalling lipid in mammalian cells, where it functions as a second-messenger precursor in response to agonist-dependent activation of phospholipase C (PLC) but also operates as a signalling molecule on its own. Much of the recent knowledge about it has come from a new technique to visualize PtdIns(4,5)P(2)in vivo, by expressing a green or yellow fluorescent protein (GFP or YFP) fused to the pleckstrin homology (PH) domain of human PLCdelta1 that specifically binds PtdIns(4,5)P(2). In this way, YFP-PH(PLCdelta1) has been shown to predominantly label the plasma membrane and to transiently translocate into the cytoplasm upon PLC activation in a variety of mammalian cell systems. In plants, biochemical studies have shown that PtdIns(4,5)P(2) is present in very small quantities, but knowledge of its localization and function is still very limited. In this study, we have used YFP-PH(PLCdelta1) to try monitoring PtdIns(4,5)P(2)/PLC signalling in stably-transformed tobacco Bright Yellow-2 (BY-2) cells and Arabidopsis seedlings. In both plant systems, no detrimental effects were observed, indicating that overexpression of the biosensor did not interfere with the function of PtdIns(4,5)P(2). Confocal imaging revealed that most of the YFP-PH(PLCdelta1) fluorescence was present in the cytoplasm, and not in the plasma membrane as in mammalian cells. Nonetheless, four conditions were found in which YFP-PH(PLCdelta1) was concentrated at the plasma membrane: (i) upon treatment with the PLC inhibitor U73122; (ii) in response to salt stress; (iii) as a gradient at the tip of growing root hairs; (iv) during the final stage of a BY-2 cell division. We conclude that PtdIns(4,5)P(2), as in animals, is present in the plasma membrane of plants, but that its concentration in most cells is too low to be detected by YFP-PH(PLCdelta1). Hence, the reporter remains unbound in the cytosol, making it unsuitable to monitor PLC signalling. Nonetheless, YFP-PH(PLCdelta1) is a valuable plant PtdIns(4,5)P(2) reporter, for it highlights specific cells and conditions where this lipid becomes abnormally concentrated in membranes, raising the question of what it is doing there. New roles for PtdIns(4,5)P(2) in plant cell signalling are discussed.
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Affiliation(s)
- Wessel van Leeuwen
- Section Plant Physiology, University of Amsterdam, Swammerdam Institute for Life Sciences, Kruislaan 318, NL-1098 SM, Amsterdam, The Netherlands
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Narkis G, Ofir R, Manor E, Landau D, Elbedour K, Birk OS. Lethal congenital contractural syndrome type 2 (LCCS2) is caused by a mutation in ERBB3 (Her3), a modulator of the phosphatidylinositol-3-kinase/Akt pathway. Am J Hum Genet 2007; 81:589-95. [PMID: 17701904 PMCID: PMC1950827 DOI: 10.1086/520770] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 05/08/2007] [Indexed: 11/03/2022] Open
Abstract
Lethal congenital contractural syndrome type 2 (LCCS2) is an autosomal recessive neurogenic form of arthrogryposis that is associated with atrophy of the anterior horn of the spinal cord. We previously mapped LCCS2 to 6.4 Mb on chromosome 12q13 and have now narrowed the locus to 4.6 Mb. We show that the disease is caused by aberrant splicing of ERBB3, which leads to a predicted truncated protein. ERBB3 (Her3), an activator of the phosphatidylinositol-3-kinase/Akt pathway--regulating cell survival and vesicle trafficking--is essential for the generation of precursors of Schwann cells that normally accompany peripheral axons of motor neurons. Gain-of-function mutations in members of the epidermal growth-factor tyrosine kinase-receptor family have been associated with predilection to cancer. This is the first report of a human phenotype resulting from loss of function of a member of this group.
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Affiliation(s)
- Ginat Narkis
- Morris Kahn Laboratory of Human Genetics, National Institute of Biotechnology in Negev, Beer-Sheva, Israel
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Narkis G, Ofir R, Landau D, Manor E, Volokita M, Hershkowitz R, Elbedour K, Birk OS. Lethal contractural syndrome type 3 (LCCS3) is caused by a mutation in PIP5K1C, which encodes PIPKI gamma of the phophatidylinsitol pathway. Am J Hum Genet 2007; 81:530-9. [PMID: 17701898 PMCID: PMC1950840 DOI: 10.1086/520771] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2007] [Accepted: 06/06/2007] [Indexed: 01/04/2023] Open
Abstract
Lethal congenital contractural syndrome (LCCS) is a severe form of arthrogryposis. To date, two autosomal recessive forms of the disease (LCCS and LCCS2) have been described and mapped to chromosomes 9q34 and 12q13, respectively. We now describe a third LCCS phenotype (LCCS3)--similar to LCCS2 yet without neurogenic bladder. Using 10K single-nucleotide-polymorphism arrays, we mapped the disease-associated gene to 8.8 Mb on chromosome 19p13. Further analysis using microsatallite markers narrowed the locus to a 3.4-Mb region harboring 120 genes. Of these genes, 30 candidates were sequenced, which identified a single homozygous mutation in PIP5K1C. PIP5K1C encodes phosphatidylinositol-4-phosphate 5-kinase, type I, gamma (PIPKI gamma ), an enzyme that phophorylates phosphatidylinositol 4-phosphate to generate phosphatidylinositol-4,5-bisphosphate (PIP(2)). We demonstrate that the mutation causes substitution of aspartic acid with asparagine at amino acid 253 (D253N), abrogating the kinase activity of PIPKI gamma . Thus, a defect in the phosphatidylinositol pathway leading to a decrease in synthesis of PIP(2), a molecule active in endocytosis of synaptic vesicle proteins, culminates in lethal congenital arthrogryposis.
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Affiliation(s)
- Ginat Narkis
- Morris Kahn Laboratory of Human Genetics, National Institute of Biotechnology in Negev, Beer-Sheva, Israel
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Im E, Kazlauskas A. Src family kinases promote vessel stability by antagonizing the Rho/ROCK pathway. J Biol Chem 2007; 282:29122-9. [PMID: 17684019 DOI: 10.1074/jbc.m702637200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Src family kinases (SFKs) are one of the signaling enzymes that contribute to angiogenesis, but their precise input to the various phases of the angiogenic program has not been defined. Using an in vitro model system, we discovered that SFKs promoted the formation of tubes and prevented their regression. They suppressed regression by activating the ERK pathway that antagonized the Rho/ROCK pathway, which was essential for regression. These studies reveal that SFKs contribute to several phases of the angiogenic program and identify the downstream effectors by which SFKs stabilize tubes.
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Affiliation(s)
- Eunok Im
- Schepens Eye Research Institute, Harvard Medical School, Boston, Massachusetts 02114, USA
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50
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Liu DZ, Liang HJ, Chen CH, Lin SY, Zhong WB, Ho FM, Hou WC, Lo JL, Ho YS, Lin PJ, Hung LF, Liang YC. Switch activation of PI-PLC downstream signals in activated macrophages with wortmannin. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2007; 1773:869-79. [PMID: 17488650 DOI: 10.1016/j.bbamcr.2007.03.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2006] [Revised: 03/03/2007] [Accepted: 03/26/2007] [Indexed: 10/23/2022]
Abstract
Phosphatidylinositol (4,5)-bisphosphate (PtdIns(4,5)P(2)) has been known to serve as a substrate for phosphatidylinositol 3-kinase (PI(3)K) and phosphoinositide-specific phospholipase C (PI-PLC), which can produce PtdIns(3,4,5)P(3) and inositol 1,4,5-trisphosphate (Ins(1,4,5)P(3)) and diacylglycerol (DAG), respectively. In this study, we elucidated the role of PI-PLC during the LPS-activated mouse macrophages RAW264.7 treated with PI(3)K inhibitor wortmannin. First, wortmannin treatment enhanced Ins(1,4,5)P(3) production and iNOS expression in LPS-activated macrophages. Inhibition of PI(3)K by p85 siRNA also showed an enhancement of iNOS expression. On the other hand, overexpression of PI(3)K by ras-p110 expression plasmid significantly decreased iNOS expression in LPS-activated macrophages. In addition, overexpression of wild-type or dominant-negative Akt expression plasmid did not affect the iNOS expression in LPS-activated macrophages. Second, treatment of PI-PLC inhibitor U73122 reversed the enhancement of iNOS expression, the increase of phosphorylation level of ERK, JNK and p38, and the increase of AP-1-dependent gene expression in wortmannin-treated and LPS-activated macrophages. However, NF-kappaB activity determined by EMSA assay and reporter plasmid assay did not change during LPS-activated macrophages with or without wortmannin. We propose that the inhibition of PI(3)K by wortmannin in mouse macrophages enhances the PI-PLC downstream signals, and subsequently increases the LPS induction of iNOS expression independently of Akt pathway.
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Affiliation(s)
- Der-Zen Liu
- Graduate Institutes of Biomedical Materials, Taipei Medical University, Taipei, Taiwan
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